Preheat the oven to 350 F
Slice your butter into pieces. Heat a pan on medium heat, then add in the butter. Whisk or stir the butter frequently over a medium flame. Once the butter melts, it will start to foam after a couple of minutes. Continue to stir it in the pan to make sure it cooks evenly. After about 5-6 minutes, the butter will start to brown and form brown specks at the bottom. It will smell intensely buttery and nutty. Once this happens, remove the pan from the heat and pour the butter into a bowl to cool.
Let the butter cool for 5-10 minutes, then add it into your mixing bowl with the egg, sugar, cinnamon and vanilla. Whisk together until smooth.
Add in the almond flour, tapioca flour, baking soda, baking powder and salt. Stir together until evenly incorporated.
Fold in your chocolate chunks and walnuts mix together.
Grease a 10" skillet or pie dish with cooking spray and press the cookie dough into the pan.
Bake for about 18-20 minutes, until the top is firm to touch.
Let cool for 10 minutes before slicing. Sprinkle with a touch of flakey salt
Keep stored in an airtight container for up to one week.